I have the same phone, and the main culprit is the connectors. The audio jack connector has gone a few years ago, now the USB-C is getting worse - I need to sometimes wiggle the cable to connect the charger. If I use a headphone then the smallest motion might disconnect it. This is the only reason why I'm considering getting a new phone - battery is still around 75% capacity (after 6 years of daily use!), otherwise still performant enough, runs any apps I use without a problem.